• Water Engineering Research
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• v.4 no.4
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• pp.203-214
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• 2003

The severe flood disaster by a typoon Rusa was occurred in the last year in Korea. The Rusa brought the rainfall of 870.5mm per a day in the city of Kangnung, Kangwon-do, Korea and this rainfall amount is 62% of the annual mean rainfall in this area. Our focus is to investigate the flash flood guidance and the sediment yield for the basins of small streams of Yangyang town in Kangnung area. Say, the flash flood guidance and the sediment yield by the Rusa are estimated and compared with the given informations obtained from the past flood events. As the results, the flash flood guidance and sediment yield in the study area showed much bigger values than the given informations and so we could know that the Rusa influenced the severe flood of the study area.

• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.985-994
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• 2010

Typoon Maemi landed on the southern coast of Korean Peninsula at 21:00, September 12, 2003 with a central pressure of 950 hPa. A three dimensional (3D) inundation model was established to calculate the storm surge and flooded area due to Typoon Maemi. A field survey of storm surge traces in Masan City was carried out to evaluate the inundation water depth. Hydromet-Rankin Vortex model was used to calculate the atmospheric pressure and the surface wind fields. The inundation area, storm surge and typoon-induced current were calculated using the 3D model. The peak of computed storm surge in Masan Port using the 3D model was 238 cm, and the observed peak was 230 cm. The simulated storm surge and the inundation area showed good agreement with field survey data. The comparison of the 3D and the two dimensional (2D) models of storm surge was carried out, and the 3D model was more accurate. The computed typoon-induced currents in the surface layer of Masan Bay went into the inner bay with 30~60 cm/s, while the currents in the bottom layer flowed out with 20~40 cm/s.

• 한국지형공간정보학회:학술대회논문집
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• 2005.09a
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• pp.33-116
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• 2005

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.107-119
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• 2003

Serious damages occurred in Yeongdong area of Gangwondo by typoon Rusa in August, 2002. Therefore, this study intends to investigate and analyse the characteristics of landslide having occurred in Gangneung area. 11 sites including many features of landslide were selected and scales, soil properties and a state of vegatation of slopes were investigated. It can be concluded that rainfall intensity, the velocity of the wind, geomorphology, vegatation and forest fire etc. are considered as main factors affecting occurrence of landslides in this area.

• Journal of Navigation and Port Research
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• v.34 no.2
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• pp.123-129
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• 2010

The object of this study is to develop the method of safe conducting of a vessel through stormy sea when we encounter typoon or hurricane on ocean. The scope of investigation in this paper will be limited to safe maneuvering related only with rolling motions of a vessel. The processes of investigations are as follows; Firstly, we decide a CPA(Closest Point of Approach) with the center of the storm and decide significant wave height($H_{1/3}$) by SMB method and then calculate wave height of the highest of 1000 waves($H_{1/1000}$) and other data. Secondly, we make mathematical model of rolling motions of the vessel on the stormy sea and calculate the biggest rolling angle of the vessel and etc. Thirdly, we decide the most safe maneuvering method to ride out the stormy sea. By the above mentioned method we are able to calculate the status of the stormy sea and ships motions to be encountered and ride out safely through violently rough sea.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.232-236
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• 2003

The anchor is laid on seabed and the main engine is worked to against incident environmental loads in typoon. As the main engine is broken down in the storm, the anchor chain is cutted and the vessel is drifted. Although a ship is moored by two point mooring lines to keep the her position, a ship is crashed into a rock because of typoon and the accident of oil spilling may be occured. In this paper, we studied the position-keeping of a ship which is analyized based on the slow motion maneuvering equations considering wave, current and wind. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical of MMG. The two point mooring forces are quasisatatically evaluated by using the catenary equation. The coefficeints of wind forces are modeled from Isherwood’s emperical data and the variation of wind speed is estimated by wind spectrum. The nonlinear motions of a two point moored ship are simulated considering wave, current, wind load in time domain.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.622-632
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• 1995

The present numerical study is aimed to investigate time-dependent characteristics of a two-dimensional lid-driven square cavity flow of three high Reynolds numbers, $7.5{\times}10^3$, $10^4$ and $3{\times}10^4$. A conservative convection term on irregular grids was adopted by renewing the MAC type difference schemes on regular grids. Relaxation of velocity and pressure is implemented by SOLA algorithm. In case of $Re=7.5{\times}10^3$, flow behavior converges to steady state after a transient period. But for $Re=10^4$, periodic unsteady sinusoidal fluctuation of local velocity and kinetic energy is found and continuous movements of small eddies in the secondary flow regions are also discovered. Random generation of eddies and their active migrating behavior are detected for $Re=3{\times}10^4$, resulting in complete unsteady and non-linear flow characteristics. And, an organized structure similar to a Moffat vortex is also observed from the time-mean flow patterns. Furthermore, a typoon-like vortex(TLV) appears intemittently and rotates along the separation regions and boundary layers.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.267-267
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• 2016

Extreme events, such as Winnie(1987), Rusa(2002), Maemi(2003) at sea-side urban area, resulted not only economic losses but also life losses. The Korean sea-side characterisitcs are so complicated thar the prediction of sea level rise makes difficult. Geomophologically, Korean pennisula sits on the rim of the Pacific mantle so the sea level is sensitive to the surges due to earth quake, typoon and abnormal climate changes. These environmetns require closer investigation for the preparing the inundatioin due to the sea level rise with customized prediction for local basin. The goal of this research is provide the information of inundation risk so the sea side urban basin could be more safe from the natural water disastesr.

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.8-15
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• 2003

When a typoon sets into harbour, a moored ship shows erratic motions and even mooring line failure may occur. such troubles may be caused by harbour resonance phenomena, resulting in large motion amplitudes at low frequency, which is close ti the natural frequency of th moored ship. The nonlinear motions of a ship moored to quay are simulated under external forces due to wave, current including mooring forces in time domain. The forces due to waves are obtained from source and dipole distribution method in the frequency domain. The current forces are calculated by using slow motion maneuvering equation in the horizontal plane. The wind forces are calculated from the empirical formula of ABS and the mooring forces of ropes and fenders are modeled as linear spring.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.848-857
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• 2008

In September 2007, the collapses of slopes and landslides are happened at Jeonlanamdo due to heavy rains accompanied with Typoon "Nari". The study area is the tunnel portal slope in new road construction site. This slope consists of pyroclastic rocks and has lots of faults. Particularly, the residual soils of the slope is deteriorated with yellowish mudstone layer as a results of chemical and physical weathering. This has a variety of swelling clay minerals and might be moved easily down at the gentle terrain. The inner factor of $\bigcirc\bigcirc$tunnel portal slope's collapse is the geological weak zone, the convergent topography, the inferiority of drainage and the heavy rain act on the failure as direct trigger.